双任务下楼梯行走时对下肢肌肉活动表现及加速度近似熵指数的影响

Effects of Dual-Task during Stair Descending on Lower Extremity Muscle and Approximate Entropy

目的:下楼梯时按照单任务与双任务通过进行速度、肌肉激活与行走方式等指标,探索任务难度(组间)及楼梯层数(组内)对摔倒的影响。方法:选取24名健康男性大学生作为受试者,随机顺序按进行双任务与否自第7层逐级下楼梯至第1层(分别命名为P1～P6阶段)。在股直肌、股二头肌、胫骨前肌和内侧腓肠肌肌腹粘贴表面肌电,计算积分肌电和同步收缩指数。在足跟处固定加速度计计算行走时间,在髂后上棘处固定加速度计计算近似商指数(ApEn)。所有数据采用SPSS19.0统计软件进行统计分析,若双因素重复测量方差分析后交互作用显著,通过独立法进行后续检验。结果:下楼梯的2任务比较时进行双任务的时间较单任务长且存在交互作用;独立样本T检验显示,P1、P2、P3、P5、P6阶段行走时间结果显著,积分肌电交互作用不显著,同步收缩指数的交互作用显著,组内出现差异,X轴和Y轴的近似熵指数交互作用显著,其中X轴组间P1、P4、P5阶段,Y轴P6阶段存在差异,X轴组内存在差异。结论:双任务下楼梯增加单支撑的时间提高小腿的同步收缩指数以保持平衡,身体重心摇动对外部环境的应对没有单任务稳定。因此,进行双任务时摔倒的概率比单任务大,相比进行其他任务,需要集中于下楼梯行走的任务。

Objective:The purpose of this study was to promoting the understanding of risk factors for gait velocity,patterns and muscle activations according to dual tasks during stair descending.Methods:Twenty-four sedentary young male adults(Age:27.0±1.8yrs,Weight:65.8±9.9 kg)without any lower extremity injuries participated in the study.Participants performed stair descending seven floors and their descending motion on each floor(total seven floors)was analyzed according to dual tasks.A wireless electromyography(EMG)were attached on the rectus femoris,biceps femoris,medial gastrocnemius,tibialis anterior muscle to calculate integrated EMG(iEMG)and co-contraction index(CI).The left heel accelerometer signal were calculated walking time,the PSIS signal were calculated approximate entropy(ApEn)for analyzing gait pattern.Results:The results indicated that there was an interaction of walking time and performed long time,there was significant difference between two groups at the P1,P2,P3,P5,P6.And no significant difference was found the iEMG.There was an interaction of CI in the tibialis anterior and medial gastrocnemius.The difference between ApEn of X,Y axis was statistically significant.Conclusions:Subjects showed to increase risk of fall than non dual-task during dual-task.Therefore we need to concentrate about stair descending than perform another task during stair descending.